Evaluation of social-ecological effectiveness of protected areas on the Chang tang plateau

Protected areas(PAs) play a positive role in stabilizing biodiversity and ecosystem services. The social-ecological effectiveness evaluation of PAs is helpful in directing efforts to perfect the PA system. There are two kinds of PAs in the Chang tang plateau in northwestern Tibet: the Chang tang National Nature Reserve(NNR) and the Chang tang National Ecological function Area(NEA). In this study, the ecosystem net primary productivity(NPP) and the landscape ecological index were used to evaluate the ecological effectiveness of PAs, whereas the social economic effectiveness was evaluated using indicators, such as the population density and agricultural output value per capita. The conclusions were as follows: 1) regarding ecological effectiveness from 2000 to 2015, the NPP of PAs showed a decreasing trend, but the decreasing rate of NPP slowed after the establishment of PAs. Landscape fragmentation increased and patch morphology became complicated. The spatial agglomeration of patches in the human-dominated landscapes, such as grasslands, farmlands, and towns, was enhanced except for some remote areas, wherein the disturbance of human activities is still strong. Among them, the proportion of ecological land in the NNR increased, whereas the proportion of production land decreased, which showed that natural landscape was restored to a certain extent in the NNR. The proportion of ecological land decreased and the proportion of production land increased in the NEA; in particular, the proportion of grassland increased, which showed that ecological pressure increased in the NEA. 2) Social and economic effectiveness assessment from 1990 to 2015 showed that population density and the total agricultural output value of the NNR was significantly lower than that of the NEA, whereas the per capita agricultural output value of the NNR was significantly higher than that of the NEA. The population density and per capita agricultural output value increased after the establishment of the two kinds of PAs. Population density of the NEA increased significantly, whereas the per capita agricultural output value of the NNR increased significantly. In the future, we should strengthen the management and control of human activities in the NNR, make greater efforts to reduction conflicts between nature conservation and community development in the NEA, clarify the pertinence of financial payments to the NEA, and explore new ways to harmonizing the sustainable use and effective prot